Azeotrope-like compositions of 1,1,2,3-tetrachloropropene and hydrogen fluoride

ABSTRACT

An azeotrope-like composition consisting essentially of 1,1,2,3-tetrachloropropene and hydrogen fluoride is provided, as well as methods that involve such an azeotrope-like composition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of U.S. ProvisionalApplication No. 61/110,227, filed Oct. 31, 2008, which is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention is directed to azeotrope-like compositions. Moreparticularly, the invention is directed to azeotrope-like compositionscomprising a hydrofluoroolefin and hydrogen fluoride.

2. Description of the Prior Art

Many azeotropes possess properties that make them useful as solvents.For example, azeotropes have a constant boiling point that avoidsboiling temperature drift during processing and use. In addition, whenan azeotrope is used as a solvent, the properties of the solvent remainconstant because the composition of the solvent does not change duringboiling or reflux. Azeotropes that are used as solvents also can berecovered conveniently by distillation.

However, the identification of new, environmentally-safe,non-fractionating mixtures that are commercially useful is complicateddue to the fact that azeotrope formation is not readily predictable.Therefore, industry is continually seeking new azeotrope andazeotrope-like mixtures. This invention satisfies these needs amongothers.

SUMMARY OF THE INVENTION

A heteroazeotrope-like composition has been found that consistsessentially of 1,1,2,3-tetrachloropropene (TCP) and hydrogen fluoride(HF). This azeotrope-like composition is useful as a solvent in variousapplications, such as removing surface oxidation from metals. Moreover,this azeotrope-like composition is useful as an intermediate in thesynthesis of certain hydrofluoroolefins, such as HFO-1234yf.

Accordingly, provided is an azeotrope-like composition consistingessentially of 1,1,2,3-tetrachloropropene and hydrogen fluoride.

In another aspect of the invention, provided is a method for forming anazeotropic or azeotrope-like composition comprising blending hydrogenfluoride with 1,1,2,3-tetrachloropropene at a temperature of from about0° C. to about 60° C. and at a pressure of about 7 psia to about 58 psiato produce an azeotrope-like mixture consisting essentially of about 1to about 95 weight percent hydrogen fluoride and from about 5 to about99 weight percent 1,1,2,3-tetrachloropropene.

In yet another aspect of the invention, provided is a solvent comprisingan azeotrope-like composition consisting essentially of1,1,2,3-tetrachloropropene and hydrogen fluoride.

In another aspect of the invention, provided is a sprayable compositioncomprising an azeotrope-like composition consisting essentially of1,1,2,3-tetrachloropropene and hydrogen fluoride.

And in other aspect of the invention, provided is a method for removingsurface oxidation from a substrate comprising contacting an oxidizedsurface of a metal substrate with a solvent comprising the novelazeotrope-like compositions described herein under conditions effectiveto remove an amount of metal oxides from said surface

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a plot of the vapor pressures of the mixtures formed inExample 2 as measured at 0, 25, and 60° C.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

The present invention provides compositions which comprise hydrogenfluoride (HF) and 1,1,2,3-tetrachloropropene (TCP) in amounts effectiveto form an azeotrope-like composition, as well as methods involving suchazeotrope-like compositions. In certain preferred embodiments, theseazeotrope-like compositions are binary azeotropes which consistessentially of combinations of only hydrogen fluoride with TCP.

As used herein, the term “azeotrope-like” relates to compositions thatare strictly azeotropic and/or that generally behave like azeotropicmixtures. An azeotropic mixture is a system of two or more components inwhich the liquid composition and vapor composition are equal at thestated pressure and temperature. In practice, this means that thecomponents of an azeotropic mixture are constant-boiling or essentiallyconstant-boiling and generally cannot be thermodynamically separatedduring a phase change. The vapor composition formed by boiling orevaporation of an azeotropic mixture is identical, or substantiallyidentical, to the original liquid composition. Thus, the concentrationof components in the liquid and vapor phases of azeotrope-likecompositions change only minimally, if at all, as the composition boilsor otherwise evaporates. In contrast, boiling or evaporatingnon-azeotropic mixtures changes the component concentrations in theliquid phase to a significant degree.

As used herein, the terms “heteroazeotrope” and “heterogeneousazeotrope” mean an azeotrope-like composition comprising a vapor phaseconcurrently with two liquid phases.

As used herein, the term “consisting essentially of”, with respect tothe components of an azeotrope-like composition, means the compositioncontains the indicated components in an azeotrope-like ratio, and maycontain additional components provided that the additional components donot form new azeotrope-like systems. For example, azeotrope-likemixtures consisting essentially of two compounds are those that formbinary azeotropes, which optionally may include one or more additionalcomponents, provided that the additional components do not render themixture non-azeotropic and do not form an azeotrope with either or bothof the compounds (e.g., do not form a ternary azeotrope).

The term “effective amounts” as used herein refers to the amount of eachcomponent which, upon combination with the other component, results inthe formation of an azeotrope-like composition of the present invention.

The term “dispensed form” as used herein refers to a physical form of afluid as it is spread, distributed, and/or diffused over an area orthrough a volume. Examples of dispensed forms include aerosols andsprays.

In certain preferred embodiments, the azeotrope-like compositioncontains from about 1 to about 95 weight percent HF and from about 5 toabout 99 weight percent TCP, more preferably from about 5 weight percentto about 95 weight percent HF and from about 5 weight percent to about95 weight percent TCP, most preferably from about 55 weight percent toabout 95 weight percent HF and from about 5 weight percent to about 45weight percent TCP.

The composition of the present invention preferably has a boiling pointof from about 0° C. to about 60° C. at a pressure from about 7 psia toabout 58 psia. For example, a preferred azeotrope-like compositionconsists essentially of about 95±2 weight percent HF and about 9±2weight percent TCP and has a normal boiling point of about 23° C.

The azeotrope-like compositions of the present invention can be producedby combining effective amounts of TCP with HF. Any of a wide variety ofmethods known in the art for combining two or more components to form acomposition can be adapted for use in the present methods. For example,TCP and HF can be mixed, blended, or otherwise combined by hand and/orby machine, as part of a batch or continuous reaction and/or process, orvia combinations of two or more such steps. In light of the disclosureherein, those of skill in the art will be readily able to prepareazeotrope-like compositions according to the present invention withoutundue experimentation.

In another embodiment of the invention, the azeotrope-like compositionsdescribed herein can be used as a solvent, particularly a cleaningsolvent. In certain embodiments, the solvent is contacted with anoxidized surface of a metal substrate to remove or reduce at least apotion of the oxidized surface. Such solvents may be applied to thetargeted substrate via any means known in the art, such as dipping,spraying, wiping, and the like.

In certain preferred embodiments, provided is a sprayable compositioncomprising the novel azeotrope-like compositions described herein. Incertain embodiments, the sprayable composition is an aerosol. In certainthe sprayable composition further comprises other components such asinert ingredients, co-solvents, propellants, co-propellants, and thelike.

In certain embodiments, the novel azeotrope-like compositions describedherein are useful intermediates derived from during synthesis of certainhydrofluoroolefins, such as 2,3,3,3-tetrafluoropropene (HFO-1234yf). Forexample, where TCP and HF are introduced into a reactor during aHFO-1234yf synthesis reaction, at least a portion of these componentsform an azeotrope which subsequently can be recovered from theassociated reaction product stream.

In certain embodiments, method for reducing the boiling point of ahydrochloropropane is provided wherein the method comprises blendingeffective amounts of TCP and HF to form an azeotrope-like mixtureconsisting essentially of TCP and HF. Lowering the boiling point of TCPis advantageous when the TCP is used as a reactant in a vapor phasefluorination reaction. More particularly, lowering the boiling pointfacilitates vaporization of the compound and, thus, helps preventdecomposition of the compound and also reduces the amount of energyrequired by the fluorination process.

Accordingly, also provided is a method for fluorinating an organiccompound comprising (a) providing an azeotrope-like compositionconsisting essentially of TCP and HF; and (b) reacting at least aportion of said TCP in the vapor phase with a fluorinating agent toproduce at least one fluorinated organic compound, preferably ahydrofluoroolefin, more preferably a tetrafluoropropene, and even morepreferably a 2,3,3,3-tetrafluoropropene.

EXAMPLES

The invention is further illustrated in the following example which isintended to be illustrative, but not limiting in any manner.

Example 1

Approximately 9 g of 1,1,2,3-tetrachloropropene (TCP) was blended in 91g of HF to at about 25° C. and about 14.6 psia. The formation of aheterogeneous azeotrope-like composition was observed.

Example 2

TCP and HF were blended to form heterogeneous azeotrope mixtures atdifferent compositions. The vapor pressures of the mixtures are measuredat about 0, 25, and 60° C. The results of these measurements areprovided in Table 1.

TABLE 1 P-T-X of TCP/HF System. Pressure (Psia) Wt. % HF T = 0° C. T =25° C. T = 60° C. 0.00 0.0 0.1 0.24 8.70 6.71 17.64 51.81 14.58 7.4818.57 51.95 19.59 8.16 19.34 52.10 24.14 8.75 19.93 53.75 28.55 8.9420.17 54.63 35.25 9.19 20.61 55.02 42.09 9.19 20.61 55.74 47.61 9.1920.61 55.94 52.18 9.38 21.00 56.28 55.06 9.96 21.63 57.25 66.41 8.8920.31 56.28 74.89 6.95 17.84 54.72 100.0 6.87 17.82 52.43

The data in Table 1 demonstrates that these mixtures exhibitazeotrope-like characteristics since the vapor pressures of mixtures ofTCP and HF are higher, at all indicated blend proportions, than TCP andHF alone, i.e. as indicated in the first and last rows when HF is 0.0wt. % and TCP is at 100.0 wt % as well as when TCP is at 0.0 wt. % andHF is at 100.0 wt. %.

The data from Table 1 is depicted graphically in FIG. 1.

Example 3

This example demonstrates the azeotropic-like properties of TCP/HFmixtures via Vapor-Liquid-Liquid Equilibrium (VLLE).

Approximately 14.4 g of 1,1,2,3-tetrachloropropene (TCP) was blendedwith 15.7 g of HF to form, upon visual observation, a heterogeneousmixture at 23° C. A second mixture of 53 wt % TCP and 47 wt % HF wasprepared. The vapor compositions of the two mixtures were sampled atroom temperature of 23° C. The result shows that the weight percent ofHF in the vapor of mixture 1 is 90.9, and the weight percent of HF inthe vapor of mixture 2 is 91.5. Accordingly, an azeotrope-likecomposition was formed having about 91±2 wt. % HF at 23° C.

1. A composition comprising an azeotrope-like mixture consistingessentially of 1,1,2,3-tetrachloropropene and hydrogen fluoride.
 2. Thecomposition of claim 1 wherein said azeotrope-like mixture consistsessentially of from about 1 to about 95 weight percent hydrogen fluorideand from about 5 to about 99 weight percent 1,1,2,3-tetrachloropropene.3. The composition of claim 2 wherein said composition consistsessentially of said azeotrope-like mixture.
 4. The composition of claim2 wherein said composition consists of said azeotrope-like mixture. 5.The composition of claim 2 wherein said composition is in a dispensedform selected from the group consisting of aerosol and spray.
 6. Thecomposition of claim 1 wherein said azeotrope-like mixture consistsessentially of from about 5 to about 95 weight percent hydrogen fluorideand from about 5 to about 95 weight percent 1,1,2,3-tetrachloropropene.7. The composition of claim 6 wherein said composition consistsessentially of said azeotrope-like mixture.
 8. The composition of claim6 wherein said composition consists of said azeotrope-like mixture. 9.The composition of claim 6 wherein said composition is in a dispensedform selected from the group consisting of aerosol and spray.
 10. Thecomposition of claim 1 wherein said azeotrope-like mixture consistsessentially of from about 55 to about 95 weight percent hydrogenfluoride and about 5 to about 45 weight percent1,1,2,3-tetrachloropropene.
 11. The composition of claim 10 wherein saidcomposition consists essentially of said azeotrope-like mixture.
 12. Thecomposition of claim 10 wherein said composition consists of saidazeotrope-like mixture.
 13. The composition of claim 10 wherein saidcomposition is in a dispensed form selected from the group consisting ofaerosol and spray.
 14. The composition of claim 1, wherein saidazeotrope-like mixture has a boiling point of from about 0° C. to about60° C. at a pressure of from about 7 psia to about 58 psia.
 15. Thecomposition of claim 1 further comprising at least one componentselected from inert diluent, cleaning agent, propellant, co-propellant,and co-solvent.
 16. The composition of claim 15 having at least about 50weight percent of said azeotrope-like mixture.
 17. The composition ofclaim 15 having at least about 95 weight percent of said azeotrope-likemixture.
 18. A method for fluorinating an organic compound comprising:a. providing an azeotrope-like composition consisting essentially of1,1,2,3-tetrachloropropene and hydrogen fluoride; and b. reacting atleast a portion of said 1,1,2,3-tetrachloropropene in the vapor phasewith a fluorinating agent to produce at least one fluorinated organiccompound.
 19. A method for reducing the boiling point of ahydrochloropropane comprising blending effective amounts of1,1,2,3-tetrachloropropene and hydrogen fluoride to form anazeotrope-like mixture consisting essentially of1,1,2,3-tetrachloropropene and hydrogen fluoride.